How to use synchronization

[SGUZMAN7]

I spent 5 hours Synchronizing and then it completed. How do i get it to take snap and synchronize again? Do i just run the job again until i can shutdown the server?

[yaroslav (staff)]

Synchronization is available only during conversion.
If you are going to build a backup or active-passive replication solution, V2V is not the right fit as it performs a full backup.

[mislav]

Hi Guys,

I am doing a migration of Vms from VCenter/ESXi to Hyper-V. I have just finished testing how to use the synchronization feature. I can't find any documentation on it.
From what I can see. It performs a snapshot on first copy, it then copies the initial disk (on my system it is copying at approx 410Mbps). Once the initial copy is completed, it creates a 2nd snapshot, it then runs a new copy which runs about 25% quicker. Once the 2nd copy is finished, the process is complete but there is only one VHDX file on the Hyper-V end so it looks like it has merged the data from the 2nd copy on the fly. Is this correct?
Also, my original disk was 60GB and the snapshot was only 1GB but the time to copy was 20mins for the 1st copy and 15mins for the 2nd copy.
Am I reading this right? I am trying to understand the use case for this.
NOTE: I have a couple of servers that are approx 2-3TB so synchronization may be a good fit but if the 2nd synch only performs 25% quicker and finishes after one snapshot and doesn't shutdown the original VM and startup the new VM then this function may not do what I need.

Two years later... Has anyone actually found a better solution? I’m facing basically the same problem. This solution would be perfect if the sync phase took only a few minutes (resulting in minimal downtime), but the sync process is too slow—almost as slow as the initial full transfer. This defeats the purpose of a 'hot migration' because it ends up being slower than a standard offline migration.
Not to mention the lack of documentation from StarWind for this tool. They didn't even integrate a warning message into the software to tell you when you actually need to turn the VM off.

[yaroslav (staff)]

Hi,
I can relate to your frustration.
Sadly, the change is on the road map. I can't provide a realistic ETA for it.
Synchronization is, effectively, the snapshot merge. I am not sure if it can be sped up on V2V end.